心存疑虑 英文怎么说？

心存疑虑
doubt （这个比较常用）
suspect

我对他们的未来心存疑虑。
There 's some doubt in my mind about their future.

我对他是否有能力购买心存疑虑。
There 's some doubt in my mind if he can afford to buy it.

There're some doubt in one's mind

has/have some doubts

i wonder.